Like many digital non-natives (are we digital tourists? Immigrants? Reluctant asylum seekers?), I like to assume that social media trends I don’t understand can’t be that important, otherwise I would somehow, maybe telepathically, understand them. So it was with the triple-brackets around a person’s name on Twitter. On my timeline, which is roughly divided between foodies and lefties, people started to triple-bracket themselves – (((like this))) – but this is a response to and subversion of the main trend, which is to triple-bracket others.

What does it mean?

The brackets, known as “echoes”, are a far-right invention, to identify Jewish Twitter users, so that other antisemites can then attack them online. The raising of a rabble is not limited to antisemites – misogynist fury can likewise manifest in epic crowds, virtual-baying. But there is something about ((())) that is uniquely unnerving, the secrecy conferring a sense of a developed and organised network of hate. Jonathan Weisman, deputy Washington editor of the New York Times, described how it played out for him following the publication of his article on Donald Trump. A Twitter user triple bracketed him in a tweet, and he was subjected to a sudden hurricane of abuse, images of concentration camps and death threats that has yet to abate.

Who else uses it?

Old-school white supremacists have new allies: the self-styled alternative right, or “alt-right”, promulgators of online viciousness, much of it racist in theme. They cite the rise of Trump as a key factor in their growing confidence, as well as the refugee crisis. They think of themselves as modern, which, to give them credit, they are, since they have managed to weaponise the internet, turning virtual threats into real-life fear. Their tools are hacking and doxing (publishing personal details, home addresses and other whereabouts, of victims), and often just marshalling huge amounts of hostility on to a single target.

Why are people putting the echo symbol around their own name?

Those who want to show solidarity with Jewish people who have been attacked, and indeed, Jewish people generally. The Twitter user @andrewcb explains: “It’s a bit like the urban legend about the Danish king wearing a yellow star during the occupation.” As the myth has it, King Christian X wore a star in response to Nazi requests that he solve his “Jewish problem”, and all the Danish people followed suit, which led the identifier to become meaningless.

Nothing makes the alt-right angrier than the puckish appropriation of a tag, trope or practice in order to mock it and show solidarity with those it is intended to offend. Reclaiming symbols, words and hashtags isn’t new: recent examples include the #1in5Muslims hashtag, in response to the Sun’s radically unintelligent reading of a poll, and #DistractinglySexy, in which female scientists responded to Tim Hunt’s evaluation of women in his field by tweeting portraits of themselves at work in the lab or outdoors. Those women came in for some incredible abuse – as vilified for objecting to Hunt as he was for his original remark. On the internet, sexism and objecting to sexism are basically interchangeable, in terms of what they cost. But they did it anyway.